A video has emerged showing the extraordinary “knock on the roof” technique used by the Israeli military to warn Palestinian civilians of an impending missile strike.

The footage was uploaded to YouTube yesterday by the Gaza-based Watania news agency, and shows from extremely close quarters a small missile striking the roof of a house across the street.

According to the caption, around 15 minutes later – though most of this time has been edited out of the final clip itself – two fully-armed missiles from an F16 jet strike one after the other, blasting the front of the house away and sending a cloud of debris and rubble into the air.

When the dust settles, the full extent of the damage is slowly revealed, with only the exposed back half of the home still standing.

The initial projectile is part of a controversial warning system used by the Israeli military to make people evacuate structures it has identified as having possible links to Hamas militants.

Meanwhile, as the death toll creeps ever higher and hundreds of Palestinians flee Gaza, Israel’s Prime Minister has said that its mission to take down Hamas “might take a long time”.

The so-called “knock on the roof” technique has been condemned by Amnesty International’s Philip Luther, who said: “There is no way that firing a missile at a civilian home can constitute an effective ‘warning’. Amnesty International has documented cases of civilians killed or injured by such missiles in previous Israeli military operations on the Gaza Strip.”

The Watania agency reported that the home in this case belonged to Samir Nofal, who was able to get out in time along with his family and neighbours.

In the past, video footage has shown Israeli drone operators diverting missiles when it is realised there are still people on the roof of a target.

A senior Air Force officer told Haaretz, “There was nothing to be done, the munition was in the air and could not be diverted… Although you see [the family members] running back into the house, there was no way to divert the missile.”

The attack saw six children killed, alongside the Hamas commander Odeh Kaware. Israeli officials described it as a “legitimate target” in the wake of the barrage of rockets fired on Israel from Gaza in recent days and weeks.